United States Court of Appeals
                      For the First Circuit


No. 09-1135

              SONIA I. JIMÉNEZ; LOURDES MOLINA-DOVAL,

                      Plaintiffs, Appellants,

                                v.

     LUIS ALFONSO RODRÍGUEZ-PAGÁN; ALIDA RAMONA BINET-MIESES;
       CONJUGAL PARTNERSHIP RODRÍGUEZ-BINET; FEDERICO TOMÁS
   RODRÍGUEZ-BINET a/k/a Tommy Rodríguez; ISABELA BEACH COURT,

                      Defendants, Appellees.


          APPEAL FROM THE UNITED STATES DISTRICT COURT

                  FOR THE DISTRICT OF PUERTO RICO

        [Hon. Salvador E. Casellas, U.S. District Judge]


                              Before

                   Torruella, Lipez and Howard,
                          Circuit Judges.



     Irma R. Valldejuli for appellants.
     Mónica I. De Jesús Santana, with whom Fiddler González &
Rodríguez. PSC, was on brief, for appellees.



                           March 1, 2010
              HOWARD, Circuit Judge. This case calls on us to navigate

the turbulent waters of Colorado River abstention.                   That doctrine,

established in Colorado River Water Conservation District v. United

States, 

(1976), allows federal courts in limited

instances      to    stay   or    dismiss    proceedings      that    overlap    with

concurrent litigation in state court.

              The plaintiffs here originally sued in federal district

court, asserting diversity jurisdiction.                 They later commenced an

identical action in a Puerto Rico Commonwealth court during what

they considered to be a burdensomely long pendency of a motion to

dismiss for failure to join an indispensable party.                        The federal

court eventually granted the motion to dismiss, leaving the action

in   the    Commonwealth     court    to    proceed      alone.      The    plaintiffs

appealed from the federal dismissal and now ask us to reinstate the

diversity      suit    to   its    parallel      track    alongside    the     ongoing

Commonwealth litigation.            The defendants argue not only that we

should affirm the dismissal for lack of an indispensable party, but

also,      among    other   things,   that       the   Commonwealth-court       action

provides an alternative ground for disposing of the federal case

under Colorado River.            We conclude that the narrow conditions for

Colorado River abstention are met here.                    We therefore stay the

federal proceedings pending the outcome of the Commonwealth-court

case.



                                           -2-
I. Background

          Since the district court did not reach the merits, we

provide a "condensed version of the dispute."     Tell v. Trs. of

Dartmouth Coll., 

, 418 (1st Cir. 1998).    On December

22, 1998, Manuel Molina-Godinez, the plaintiffs' decedent, sold the

defendants 100% of the stock in an apartment complex development

known as Isabela Beach Court.     Molina-Godinez agreed to manage

Isabela Beach Court in exchange for a monthly fee and 18% of the

proceeds after the complex's completion and the sale of all units.

In addition, before construction began, Molina-Godinez verbally

agreed to buy one of the penthouses in Isabela Beach Court for

$220,000, and the defendants reserved the unit for him.       This

agreement was later confirmed in writing.   For reasons unspecified

at this stage, the defendants dispute the scope and validity of

these agreements.

          On January 3, 2003, Molina-Godinez died. Construction of

Isabela Beach Court was completed at some point after his death and

all of the units were sold successfully.       On March 27, 2007,

Molina-Godinez's widow, plaintiff Sonia I. Jiménez, commenced an

action in the federal district court for the District of Puerto

Rico asserting that she was entitled to half of her late husband's

18% share, which had never been paid.   Additionally, she sought to

exercise his option on the penthouse apartment that had allegedly

been reserved for him.   Because Jiménez was a Florida resident and


                                -3-
the defendants were all Puerto Rico residents, she claimed that the

district court had diversity jurisdiction over the matter.

          The defendants moved to dismiss for failure to join an

indispensable party under Rule 19 of the Federal Rules of Civil

Procedure.    They argued that the case could not proceed without

Molina-Godinez's three other heirs, two of whom were also Puerto

Rico residents.    Because joinder of the Puerto Rico heirs would

defeat complete diversity, the defendants maintained, dismissal was

compulsory.

          On August 10, 2007, Jiménez amended the complaint to join

the one diverse heir while still excluding the non-diverse heirs.

She also altered her theory of the case, explaining that she was

now seeking the contractual proceeds on behalf of Molina-Godinez's

estate rather than for herself alone.   She claimed that she could

adequately protect the interests of the non-diverse heirs and that,

as a result, the action did not depend on their joinder.       The

amended complaint asked the court to award any judgment to the

estate, where it could be allocated to heirs and creditors by a

Puerto Rico probate court at some later date.

          The addition of the diverse heir as a named plaintiff did

not, however, affect the substance of the defendants' argument.

The defendants renewed their motion to dismiss, maintaining that

Jiménez was not an adequate representative of the estate and that

an adverse judgment could affect the non-diverse heirs' interests.


                                -4-
According to them, neither the case's new posture nor the joinder

of the one diverse heir would lessen the indispensability of the

non-diverse heirs.   The plaintiffs filed their response three days

later.

          Over six months passed without any further action from

the court.   On March 27, 2008, the plaintiffs sought to learn the

status of the pending motion to dismiss, but the docket does not

indicate a response from the court.    On August 29, 2008, after an

additional five months, the plaintiffs filed a parallel complaint

in the Court of First Instance for the Commonwealth of Puerto Rico.

Unlike the federal action, this second suit joined all of Molina-

Godinez's heirs as parties.

          On December 12, 2008, the district court granted the

defendants' motion to dismiss.     Jiménez v. Rodríguez-Pagán, 

(D.P.R. 2008).     This appeal followed.   Meanwhile, the

Commonwealth action has progressed in due course and is now into

the discovery stage.

II. Discussion

          The defendants-appellees present three different possible

grounds to deny appellate relief to the plaintiffs-appellants.

First, they argue that this case involves matters that fall within

the probate exception to diversity jurisdiction and thus cannot be

adjudicated in federal court. Second, they reiterate their Rule 19

claim that the non-diverse heirs remain indispensable.      Finally,


                                 -5-
they ask us to abstain under Colorado River and allow the Puerto

Rico court to resolve the case.          Though we reject the first of

these arguments and harbor considerable skepticism as to the

second, we ultimately agree that this case warrants Colorado River

abstention.1

                        A. The Probate Exception

             It has been said that "[t]he probate exception is one of

the most mysterious and esoteric branches of the law of federal

jurisdiction."      Dragan v. Miller, 

, 713 (7th Cir.

1982).     Once more unto the breach.2

             The probate exception is a judge-made doctrine stemming

from the original conferral of federal equity jurisdiction in the

Judiciary Act of 1789. The ambit of that jurisdiction, coterminous

with that exercised by the framers' contemporaries in the English

courts of chancery, "did not extend to probate matters."       Markham

v. Allen, 

, 494 (1946).       The Supreme Court accordingly

held in Markham that federal courts have no authority to "interfere

with the probate proceedings or assume general jurisdiction of the


     1
      Under different circumstances, we might proceed directly to
the dispositive Colorado River analysis, bypassing the other two
questions. In this case, however, a cursory treatment of those
questions does not suffice. Were the probate exception to apply
here, we would have no subject matter jurisdiction over this
dispute, and we think it appropriate to determine our own
jurisdiction at the outset. The Rule 19 issue merits its own
analysis because it factors into our eventual determination to
abstain.
     2
         See William Shakespeare, King Henry the Fifth, act 3, sc. 1.

                                  -6-
probate or control of the property in the custody of the state

court."    

the probate exception has proven easier than

applying it."      Umsted v. Umsted, 

, 20 n.2 (1st Cir.

2006).    After Markham, just what would constitute "interfere[nce]

with the probate proceedings" proved notoriously difficult to pin

down.     When we last had the opportunity to consider the doctrine

nearly a decade ago, we acknowledged that "the precise scope of the

probate exception has not been clearly established."            Mangieri v.

Mangieri,    

,   2   (1st   Cir.   2000)   (internal   brackets

omitted).

            Since then, the Supreme Court has revisited the issue and

illuminated matters somewhat.         In Marshall v. Marshall, the Court

explained that

            the “interference” language in Markham [is]
            essentially a reiteration of the general
            principle that, when one court is exercising
            in rem jurisdiction over a res, a second court
            will not assume in rem jurisdiction over the
            same res.      Thus, the probate exception
            reserves to state probate courts the probate
            or annulment of a will and the administration
            of a decedent's estate; it also precludes
            federal courts from endeavoring to dispose of
            property that is in the custody of a state
            probate court.   But it does not bar federal
            courts from adjudicating matters outside those
            confines   and    otherwise   within   federal
            jurisdiction.

, 311-12 (2006) (citations omitted).              Marshall made

clear that the scope of the probate exception is "distinctly


                                      -7-
limited."    

cf. Mooney v. Mooney, 

, 248 (1st

Cir.   2006)   (noting   that    the   Supreme   Court   in   Marshall   also

emphasized the narrow scope of the domestic relations exception).

            The case before us does not fall within that limited

scope.    "[W]here exercise of federal jurisdiction will result in a

judgment that does not dispose of property in the custody of a

state probate court, even though the judgment may be intertwined

with and binding on those state proceedings, the federal courts

retain their jurisdiction."        Lefkowitz v. Bank of N.Y., 

, 106 (2d Cir. 2007).        The only property at issue in this case

is the proceeds from the sale of the Isabela Beach Court units and

the penthouse apartment on which Molina-Godinez allegedly held an

option to purchase.      Because neither the money nor the apartment

are yet part of the decedent's estate, neither are yet in the

custody of a Puerto Rico probate court.           Indeed, the very relief

sought here is enlargement of the decedent's estate through assets

not currently within it.           While divvying up an estate falls

squarely within the probate exception, merely increasing it does

not.     Gustafson v. zumBrunnen, 

, 400 (7th Cir. 2008)

(finding that the probate exception did not apply because "the

judgment sought would just add assets to the decedent's estate"

rather than "reallocat[ing] the estate's assets among contending

claimants or otherwise interfer[ing] with the probate court's

control over and administration of the estate").


                                       -8-
                               B. Rule 19

          We review a district court's Rule 19 determinations for

abuse of discretion.     Picciotto v. Cont'l Cas. Co., 

, 14-

15 (1st Cir. 2008).     Because the decision to dismiss for lack of an

indispensable   party     "involve[s]    the   balancing    of   competing

interests and must be steeped in pragmatic considerations," 

(internal quotation marks omitted), we will reverse only if "the

district court makes an error of law or relies significantly on an

improper factor, omits a significant factor, or makes a clear error

of judgment in weighing the relevant factors." 

(internal

citations and quotation marks omitted).

          Rule 19 is designed to protect the interests of parties

who are not yet involved in ongoing litigation.            To measure how

critical those interests are, the rule instructs courts to engage

in a two-part analysis.     See Pujol v. Shearson Am. Exp., Inc., 

, 134 (1st Cir. 1989).          Parties should be joined, when

feasible, if they are "necessary" to the action according to the

criteria laid out in Rule 19(a).3        If a necessary party cannot be


     3
      The term "necessary" is a vestige of a superseded version of
Rule 19 and no longer appears in the text. Rule 19(a) now speaks
only of "Persons Required to be Joined if Feasible." Nevertheless,
many circuits (including this one) continue to cling to the
traditional nomenclature.    See Confederated Tribes of Chehalis
Indian Reservation v. Lujan, 

, 1501 n.1 (9th Cir.
1991) (O'Scainnlain, J., concurring in part and dissenting in
part). Lest there be any confusion, the word is used as a term of
art and signifies desirability rather than actual necessity.
Parties are not truly necessary in the vernacular sense of the word
"unless and until they satisfy the terms of Rule 19(b)." 

in the action without divesting the court of subject-matter

jurisdiction,    Rule    19(b)   lays      out   additional   criteria    for

determining whether that party is "indispensable."             If the court

finds that party is anything less than indispensable, the case

proceeds without her.     If, on the other hand, the court finds that

the litigation cannot proceed in the party's absence, the court

must dismiss the case.      See B. Fernandez & Hnos, Inc. v. Kellogg

USA, Inc., 

, 23 (1st Cir. 2008).

           Ultimately, the unsettled state of governing Puerto Rico

law hampers our ability to adjudicate this issue definitively.

Assuming for the purposes of argument that the district court

exercised its discretion properly in finding that the non-diverse

heirs were necessary parties under Rule 19(a), we proceed directly

to the indispensability analysis under Rule 19(b).            See Delgado v.

Plaza Las Americas, Inc., 

, 3 n.2 (1st Cir. 1998) (per

curiam) (noting that parties cannot be indispensable under Rule

19(b) unless they are first deemed necessary under Rule 19(a)).

The "critical question" in the Rule 19(b) context is "'whether in

equity   and   good   conscience'   the     action   may   proceed   in   [the

necessary party]'s absence." B. 

(quoting

Fed. R. Civ P. 19(b)).    To answer that question, the district court

must consider four factors specified in the Rule:

           (1)the extent to which a judgment rendered in
           the person's absence might prejudice that
           person person or the existing parties; (2) the
           extent to which any prejudice could be

                                    -10-
          lessened   or  avoided   by   (A)   protective
          provisions in the judgment; (B) shaping the
          relief; or (C) other measures; (3) whether a
          judgment rendered in the person's absence will
          be adequate; and (4) whether the plaintiff
          would have an adequate remedy if the action
          were dismissed for non-joinder.

Fed. R. Civ. P. 19(b).

          The    district   court    emphasized   the   first    and   third

factors, finding that a judgment rendered in the non-diverse heirs'

absence could potentially prejudice their interests.            It reasoned

that since each heir possesses a right to part of Molina-Godinez's

estate, any ruling on the sums due to the estate under the alleged

contract would affect each heir's individual portion.           In order to

adequately protect his or her interest in that portion, each heir

was therefore entitled to participate in the litigation, even to

the point of eliminating federal diversity jurisdiction.

          We are not so sure.       In Puerto Rico, the decedent's as-

yet undivided estate is known as a community of property.               See,

e.g., Arias-Rosado v. Gonzalez Tirado, 

, 99

(D.P.R. 2000).    On several occasions, the federal district court

for the District of Puerto Rico has interpreted Puerto Rico law to

provide that an individual participant in a community of property

does not impair other participants' interests merely by asserting

common legal rights to the property while the other participants

are absent.     "Any judgment in favor of one or more participants

benefits all other participants in a community of property whereas


                                    -11-
an adverse judgment only prejudices the one who filed the judicial

action." 

marks omitted); accord Rodriguez-

Rivera v. Rivera Rios, No. 06-1381, 

, at *3 (D.P.R.

Mar. 5, 2009); Ruiz-Hance v. P.R. Aqueduct & Sewer Auth., 596 F.

Supp. 2d 223, 230 (D.P.R. 2009); Cintron v. San Juan Gas, 79 F.

Supp. 2d 16, 19 (D.P.R. 1999).         In Arias-Rosado, a Rule 19

challenge to a survivorship action, the court went on to hold that

"a favorable judgment to [the individual heir litigating in federal

court] will be dispositive of the survivorship claim and benefit

the absent heirs.      However, an unfavorable judgment will only

prejudice her and not the absent heirs[,] who still will have

available the suit filed in state court wherein they asserted the

survivorship 

; see also Rodriguez-

Rivera, 

at *3; 

–30; Cintron, F. Supp. 2d at 19.

          Taking these cases at face value, as the plaintiffs urge

us to, it appears that the federal suit here is something of a free

shot for the non-diverse heirs.    Success inures to their benefit

while failure is costless.   Surely there can be no impairment when

they stand to lose nothing.     If the plaintiffs are providing a

correct statement of the local law, they would appear to be the

best of all possible representatives for the absentees' interests:

the kind that may very well help but cannot hurt.    See 

("If an absent party's interests are the same as those


                                -12-
of an existing party, and the existing party will adequately

protect those interests, this bears on whether the absent party's

interest will be impaired by its absence from the litigation.").

          At    this    juncture,   however,   we   cannot     state   this

proposition as anything other than a conditional hypothetical. The

plaintiffs' interpretation of Puerto Rico community property law is

far from certain.      To begin with, the cases on which the plaintiffs

rely sound exclusively in tort.        Seizing on this, the defendants

have urged us to limit the applicability of those cases to wrongful

death and survivorship actions. When pressed at oral argument, the

plaintiffs could not cite a single authority suggesting that their

interpretation of the relevant law extends to contract claims.

          This puts us in an awkward position.      On the one hand, we

would find it somewhat strange if the rule did indeed govern non-

torts actions yet had failed to produce any reported decisions to

that effect.    It is hard to say that the district court abused its

discretion when the ostensible abuse is a matter of unsettled law.

On the other hand, none of the four cases that the plaintiffs cite

facially limits itself to tort claims.         Those cases draw their

logical force not from any idiosyncrasy in Puerto Rico's tort law,

but from Puerto Rico's community-of-property law.            This may make

the defendants' argument a good candidate for a distinction without

a difference.    Contractual proceeds due to the decedent belong to

the undivided estate just as much as a wrongful death judgment.


                                    -13-
All things considered, we have an insufficient basis to accept

either the plaintiffs' or the defendants' readings of the case law.

          A second difficulty remains. Suppose that the plaintiffs

here are successful in securing some monetary damages under the

contract, but not the full amount that they seek.                Does that

constitute a successful judgment sufficient to bind the non-diverse

heirs under the plaintiffs' theory of the law, or is it instead an

adverse judgment that would leave those heirs free to double down

in the second suit?     The plaintiffs do not attempt to answer this

question, and, unaware of any authority one way or the other,

neither can we.

          In sum, we are ill equipped to rule on this question of

Puerto Rico law.     As this question may very well determine the non-

diverse heirs' indispensability here, we are equally ill equipped

to rule on the ultimate question of joinder.              Under different

circumstances, we would consider certifying the underlying question

to the Supreme Court of Puerto Rico. See Muniz-Olivari v. Stiefel

Labs., Inc., 

, 39–40 (1st Cir. 2007).               As the next

section makes clear, though, that consideration is obviated by the

parallel litigation ongoing in the Commonwealth court.

                      C. Colorado River Abstention

          It   has    long   been   established   that   the   presence   of

parallel litigation in state court will not in and of itself merit

abstention in federal court.        See McClellan v. Carland, 217 U.S.


                                    -14-
268, 282 (1910); Stanton v. Embrey, 

, 554 (1876).

Concurrent federal-state jurisdiction over the same controversy

does not generally lessen the federal courts' "virtually unflagging

obligation . . . to exercise the jurisdiction given them."         Colo.

.        At the same time, the Supreme Court in

Colorado River acknowledged that this obligation is not infinite.

In special cases, the pendency of a similar action in state court

may merit federal abstention based on "considerations of wise

judicial     administration"     that     counsel   against   duplicative

lawsuits.4    

and quotation marks omitted).

This "fourth category" of abstention has come to be known as the

Colorado River doctrine.5      See Fuller Co. v. Ramon I. Gill, Inc.,

, 309 n.3 (1st Cir. 1986) (observing that Colorado

River created a fourth category of abstention beyond the "three

traditional branches").



     4
      As with other forms of abstention, our decision to decline
jurisdiction under Colorado River may be sua sponte. See Bellotti
v. Baird, 

, 143 n.10 (1976); Guillemard-Ginorio v.
Contreras-Gomez, 

, 517–18 (1st Cir. 2009); Currie v.
Group Ins. Comm'n, 

, 9 n.7 (1st Cir. 2002). We therefore
have discretion to review the matter on appeal even if it was not
raised in the court below.
     5
      The first three forms of abstention are Pullman-type
(avoiding a constitutional determination by allowing a state court
to construe state law), Burford-type (deferring to a state
regarding difficult questions of state law that involve significant
policy considerations), and Younger-type (invoking federal
jurisdiction to restrain criminal proceedings). See Colo. 

–17; Villa Marina Yacht Sales, Inc. v. Hatteras
Yachts, 

, 12 n.8 (1st Cir. 1990).

                                   -15-
            The crevice in federal jurisdiction that Colorado River

carved is a narrow one.       Of all the abstention doctrines, it is to

be approached with the most caution, with "[o]nly the clearest of

justifications" warranting dismissal.             Colo. 

.   Our authority to find such a clear justification is confined

by an "exceptional-circumstances test,"           Moses H. Cone Mem'l Hosp.

v. Mercury Const. Corp., 

, 16 (1983), whose non-exclusive

list of factors we have drawn from Colorado River and its progeny:

            (1)   whether   either    court   has    assumed
            jurisdiction    over    a    res;     (2)    the
            [geographical] inconvenience of the federal
            forum; (3) the desirability of avoiding
            piecemeal litigation; (4) the order in which
            the forums obtained jurisdiction; (5) whether
            state or federal law controls; (6) the
            adequacy of the state forum to protect the
            parties' interests; (7) the       vexatious or
            contrived nature of the federal claim; and (8)
            respect for the principles underlying removal
            jurisdiction.

Rio Grande Cmty. Health Ctr. v. Rullan, 

, 71–72 (1st

Cir.   2005).    "No   one    factor    is    necessarily    determinative;     a

carefully    considered      judgment    taking    into     account   both    the

obligation to exercise jurisdiction and the combination of factors

counselling against that exercise is required."              Colo. 

–19.    Furthermore, "the decision whether to dismiss a

federal action because of parallel state-court litigation does not

rest on a mechanical checklist, but on a careful balancing of the

important factors as they apply in a given case, with the balance

heavily weighted in favor of the exercise of jurisdiction."                  Moses

                                       -16-
H. 

.      Unsurprisingly, the cases that satisfy

this test are few and far between.

            Yet those cases, "though exceptional, do nevertheless

exist."   Colo. 

.       From time to time, we have

exercised our discretion (or affirmed the lower court's exercise of

its own discretion) to decline jurisdiction under Colorado River,

notwithstanding the presumption in favor of assuming jurisdiction.

See, e.g., Rivera-Feliciano v. Acevedo-Vila, 

(1st Cir.

2006); Currie v. Group Ins. Comm'n, 

(1st Cir. 2002);

Liberty Mut. Ins. Co. v. Foremost-McKesson, Inc., 

(1st

Cir. 1985).

            In our view, this is such a case.      Applying the factors,

we conclude that while some are neutral to our inquiry, the balance

of them strongly favors abstention.           We begin with the neutral

factors, which may be summarized quickly.         The federal and Puerto

Rico forums are equally convenient (second factor); the Puerto Rico

forum is well equipped to protect the parties' interests (sixth

factor), see United States v. Fairway Capital Corp., 

,

43 (1st Cir. 2007) (holding that the adequacy of the state forum is

relevant only when it would disfavor abstention); there is nothing

vexatious   or   contrived   about    the   plaintiffs'   federal   lawsuit

(seventh factor); and removal jurisdiction is irrelevant here

(eighth factor).




                                     -17-
          So far, so good.       But the sum of the other four factors

convinces us that deference to the Commonwealth court is the

appropriate result here.     The first factor, the involvement of a

res, tilts toward abstention due to the plaintiffs' claim for the

penthouse apartment in Isabela Beach Court.        Though the plaintiffs

characterize this as a suit over monetary damages, both versions of

the complaint request the court to enforce the decedent's alleged

option on the apartment. There is therefore a possibility for

inconsistent dispositions of property.6

          The third factor, avoidance of piecemeal litigation, also

favors abstention, although it requires a bit more explanation.

The "piecemeal litigation" to be avoided is something more than

just the repetitive adjudication that takes place in all cases

implicating Colorado River doctrine.           Concurrent federal-state



     6
      In Levy v. Lewis, the Second Circuit observed that the res
prong of the Colorado River analysis was more concerned with the
disposition of property than the actual exercise of in rem
jurisdiction:

     The principle is often stated as a matter of
     jurisdiction:   that   a   second   court   cannot   have
     jurisdiction to proceed in rem if jurisdiction over the
     res is maintained by another court. Nevertheless, as the
     Court appeared to recognize, the principle involved is
     more accurately described as a prudential doctrine in
     which a second court with concurrent jurisdiction will
     exercise its discretion to defer to another court for the
     sake of comprehensive disposition of rights in a
     particular piece of property or in a fund.

,   965–66     (2d    Cir.    1980).   We   agree   with   this
assessment.

                                   -18-
jurisdiction over the same action will necessarily involve some

degree of "routine inefficiency that is the inevitable result of

parallel proceedings."   Villa Marina Yacht Sales, Inc. v. Hatteras

Yachts, 

, 16 (1st Cir. 1990).     That inefficiency was not

significant to the Supreme Court's decision in Colorado River and

has not contributed to any of this circuit's subsequent case law.

Were it otherwise, courts could abstain in any diversity action

that overlapped with a state-court action.       "Piecemeal litigation"

must instead refer to some additional factor that places the case

beyond the pale of duplicative proceedings.       Put differently, "[a]

duplication   of   effort,   while   wasteful,   is   not   exceptional."

Gentron Corp. v. H. C. Johnson Agencies, Inc., 

, 418

(E.D. Wis. 1978).

          We have therefore held that

          [d]ismissal is not warranted simply because
          related issues otherwise would be decided by
          different courts, or even because two courts
          otherwise would be deciding the same issues.
          Rather, concerns about piecemeal litigation
          should focus on the implications and practical
          effects of litigating suits deriving from the
          same transaction in two separate fora, and
          weigh in favor of dismissal only if there is
          some exceptional basis for dismissing one
          action in favor of the other.

KPS & Assocs., Inc. v. Designs by FMC, Inc., 

, 10–11 (1st

Cir. 2003) (internal quotation marks and citations omitted).          The

canonical example of such an exceptional basis is a clear federal

policy in favor of unified proceedings pursuant to a federal


                                 -19-
statute that is at issue in the case.              See Colo. 

–20 (finding abstention appropriate because the federal law at

issue evinced a clear policy against piecemeal adjudication of

river system water rights); cf. Moses H. 

(finding abstention inappropriate because the Federal Arbitration

Act requires piecemeal litigation if necessary to give effect to an

arbitration agreement).            But there are other reasons why the

piecemeal litigation factor might loom large in a given case.                     On

multiple   occasions,       we    have   found     an   exceptional      basis   that

counsels in favor of abstention, even though no particular federal

policy was in play.         See, e.g., 

(holding that "in light of the many underlying unresolved issues of

Puerto    Rican    law[,]    it    would      be   better   to   avoid    piecemeal

litigation"); 

(finding a risk of piecemeal

litigation that rises above routine inefficiency where parallel

state-court case was already on appeal and involved an issue of

state    law    which   could     moot   or     otherwise   inform    the   federal

litigation); Liberty Mut. Ins. 

(finding an

exceptional basis where there existed a "real possibility" that an

insurance policy might be interpreted differently in each forum,

leaving the insured with insufficient coverage after years of

paying premiums).

               We think the potential implications of proceeding in

federal court without the non-diverse heirs provides the requisite


                                         -20-
exceptional basis here. The absence of the additional heirs in the

federal action means that in all likelihood the district court

would be unable to resolve the defendants' contractual liability to

them if the case is allowed to continue.                 The district court could

determine the defendants' obligations to the diverse heirs, but the

defendants     would      need    to   look   to   the    Commonwealth     court    to

determine their obligations to the non-diverse heirs under the same

contract.      The Commonwealth action, by contrast, includes all of

the    heirs   and     can      therefore     comprehensively      adjudicate      the

defendants'     liability.          This    disparity     in   inclusiveness    thus

creates a greater practical risk of piecemeal litigation than the

baseline inefficiencies of the average exercise of concurrent

federal-state jurisdiction.            Recognizing this, other circuits have

found Colorado River abstention more appropriate when non-diverse

parties are joined in the state-court action but not the federal

action.    See Sto Corp. v. Lancaster Homes, Inc., 

,

188 (4th Cir. 2001); Federated Rural Elec. Ins. Corp. v. Ark. Elec.

Coops., Inc., 

, 298 (8th Cir. 1995); Cont'l Cas. Co. v.

Robsac Indus., 

, 1373 (9th Cir. 1991), overruled on

other grounds, Gov't Employees Ins. Co. v. Dizol, 

(9th   Cir.    1998).        We   agree.      This   potential     for    fragmented

adjudication,        to    be     distinguished      from      merely    duplicative




                                           -21-
adjudication,      warrants    consideration      in   the    Colorado    River

analysis.7

             We move next to the fifth factor, whether state or

federal law controls, which weighs particularly heavily here.                  Not

only does the dispute here turn entirely on issues of Puerto Rico

law, see Liberty Mut. Ins. 

(finding it

significant that "no federal issues are raised . . . and no federal

interest would be served by retaining jurisdiction over the case"),

but the issues that would inform our jurisdictional analysis remain

unsettled.     We have previously held that under this part of the

exceptional-circumstances test, abstention may be preferable when

the   "parties'    claims     present   particularly    novel,       unusual    or

difficult questions of legal interpretation."            Elmendorf Grafica,

Inc. v. D.S. Am. (East), Inc., 

, 52 (1st Cir. 1995);

accord KPS & 

.          As we described above, the

plaintiffs' ability to maintain complete diversity in this case

hinges on our Rule 19 analysis.         That analysis, in turn, hinges in

part on the question of whether the non-diverse heirs' interests

could be impaired if they are not joined as parties to the suit.

We cannot intelligently answer that question without some clear

indication    as   to   whether   Puerto   Rico   courts     would    apply    the



      7
      To be sure, it may not weigh as strongly as a clear federal
policy of the sort that was considered in Colorado River, but it at
least diminishes the presumption in favor of exercising federal
jurisdiction.

                                    -22-
plaintiffs' proposed community-of-property rule to causes of action

other than tort claims.          From our vantage point, we cannot say

definitively one way or the other.               The local law that would

underlie our determination on compulsory joinder would be best left

to the Puerto Rico courts to sort out.8

              The sixth factor, the order in which the courts obtained

jurisdiction, similarly points toward abstention.               The label for

this factor is something of a misnomer, as "the relative progress

of the suits is more important than the strict order in which the

courts obtained jurisdiction."             Gonzalez v. Cruz, 

, 4

(1st Cir. 1991).         "[T]he order in which jurisdiction was taken is

not a mechanical concept automatically favoring the party who files

first, but rather a concept that favors the case that is the more

advanced at the time the Colorado River balancing is being done."

.            We thus "measure which action -- the

suit in the federal court or that in the state court -- is the more

advanced in a 'pragmatic, flexible manner, with a view to the

realities of the case at hand.'" 

H. 

).         A quick comparison of the two docket sheets at issue

here       reveals    that   while   the    federal    action   foundered    on

jurisdictional          questions,    leaving   only     this   appeal,     the


       8
      Because the Commonwealth action includes the non-diverse
heirs, this question is not likely at issue there. Our deferral
therefore means that the question will not be resolved until a
future case.    We think this delay is still preferable to our
attempting to settle a state-law question of first impression here.

                                       -23-
Commonwealth action is already well into the discovery stage.9   The

Commonwealth's head start into the merits lessens the federal

court's need to exercise jurisdiction.   See Colo. 

(stating that an absence of any federal proceedings beyond

a motion to dismiss favors the surrender of jurisdiction).

          Considering all of these factors, we conclude that this

is one of the rare instances meriting Colorado River abstention.

Because of the possibility for inconsistent dispositions of a res,

the heightened potential for piecemeal litigation, the exclusive

reliance on Puerto Rico law, the unsettled nature of aspects of

that law that would inform our jurisdictional analysis, and the

more advanced progress of the litigation in the Puerto Rico court

system, we are convinced that the wisest judicial administration of

this case is to defer to the judgment of the Puerto Rico court.




     9
      Neither the parties nor, apparently, the Court of First
Instance's Spanish-language docket specify how close to trial the
Puerto Rico case actually is. Yet a significant disparity in favor
of the Commonwealth court is clear enough. As the Seventh Circuit
recently observed in an analogous situation, "[a]lthough the
precise status of discovery is not apparent from the record before
us, it is clear that various depositions have been taken in the
state case.   At the very least, the controversy appears to be
closer to a resolution in the state proceedings than in the
federal." Tyrer v. City of South Beloit, 

, 755 (7th
Cir. 2006) (internal brackets and quotation marks omitted). Since
a court engaging in Colorado River analysis should "look at the
total situation as it stands at the time of appeal," Lumen Const.,
Inc. v. Brant Const. Co., Inc., 

, 697 n.4 (7th Cir.
1985), we take judicial notice of the progress of the parallel
Commonwealth litigation.

                               -24-
            Having come to this conclusion, we must next decide

whether the appropriate disposition is a dismissal or a stay of the

proceedings.      In Moses H. Cone, the Supreme Court committed this

question    to    the   discretion    of   the    lower   courts,    finding     "no

occasion in this case to decide whether a dismissal or a stay

should ordinarily be the preferred course of action when a district

court properly finds that Colorado River counsels in favor of

deferring    to    a    parallel    state-court    

(footnote omitted); see also Arizona v. San Carlos Apache Tribe of

Ariz., 

, 570 n.21 (1983).                 Most circuits to have

considered the issue have held that a stay is always preferable

because it may likely produce the same practical result as a

dismissal while still leaving the docket open in case loose ends

remain at the conclusion of the state proceedings.                  See Moorer v.

Demopolis Waterworks & Sewer Bd., 

, 998 (11th Cir.

2004); Cigna Healthcare of St. Louis, Inc. v. Kaiser, 

,

851-52 (7th Cir. 2002); Mahaffey v. Bechtel Assoc. Prof'l Corp.,

D.C., 

, 546–47 (D.C. Cir. 1983) (per curiam); see also

Lops v. Lops, 

, 960 n.24 (11th Cir. 1998) (Kravitch,

J., dissenting); but see Cox v. Planning Dist. I Cmty. Mental

Health & Mental Retardation Servs. Bd., 

, 943 (4th Cir.

1982) (holding that dismissal is appropriate so long as "the

determinative      issues    will    unfailingly    be    resolved    within     the




                                       -25-
parameters of the state-court litigation . . . as no further action

by the district court is anticipated").

            There is no need to decide this issue categorically here.

In   this   Circuit,   Colorado   River   abstention   has   historically

resulted in a stay, see, e.g., Rivera-Feliciano; Currie; Liberty

Mut. Ins. Co., and we elect to continue that trend in this case.

Although we do not anticipate any unresolved issues remaining after

the Commonwealth case concludes, we see no harm to judicial economy

in going the more cautious route.     See LaDuke v. Burlington N. R.R.

Co., 

, 1562 (7th Cir. 1989) (noting that a stay

"protects the rights of all the parties without imposing any

additional costs or burdens on the district court") (footnote

omitted).

III. Conclusion

            Like the district court, we think that this case should

ultimately be resolved in the Puerto Rico judicial system.         But we

reach this conclusion not because of the probate exception or Rule

19, but rather because of exceptional circumstances that satisfy

Colorado River's demanding test for abstention.         Accordingly, we

vacate the district court's dismissal and remand with instructions

to stay all further proceedings.



It is so ordered.      Costs to neither party.




                                   -26-